* Make the library modular usable.
* Switch to library requirements instead of source. As source puts extra source in install targets.
* Add wave tool build to all target.
* Add missing NO_LIB usage requirements.
* Add requires-b2 check to top-level build file.
* Bump B2 require to 5.2
* Change all <source> references to <library>.
* Move inter-lib dependencies to a project variable and into the build targets.
* Update build deps.
* Introduce a new sample that checks macro naming conventions
This has a direct use in Boost's own QA checks and demonstrates
the use of macro definition and include guard callbacks, as well
as Boost.Filesystem.
